Getting optimisation issue with some CSS

[MoOx]

When I use webpack -p, I'm getting a non helping error message

ERROR in ./~/css-loader!./~/cssnext-loader!./src/index.css
Module build failed: Error: Please check the validity of the CSS block starting from the line #1
    at throwError (/.../node_modules/css-loader/node_modules/csso/lib/gonzales.cssp.node.js:399:15)
    at checkStylesheet (/.../node_modules/css-loader/node_modules/csso/lib/gonzales.cssp.node.js:1921:22)
    at Object.CSSPRules.stylesheet (/.../node_modules/css-loader/node_modules/csso/lib/gonzales.cssp.node.js:365:40)
    at _getAST (/.../node_modules/css-loader/node_modules/csso/lib/gonzales.cssp.node.js:409:38)
    at exports.srcToCSSP (/.../node_modules/css-loader/node_modules/csso/lib/gonzales.cssp.node.js:2287:16)
    at Object.exports.srcToCSSP (/.../node_modules/css-loader/node_modules/csso/lib/gonzales.cssp.node.js:2292:16)
    at Object.exports.parse (/.../node_modules/css-loader/node_modules/csso/lib/cssoapi.js:7:21)
    at Object.module.exports (/.../node_modules/css-loader/index.js:18:18)
 @ ./src/index.css 4:14-293

In this index.css I just have some inlined @import, so this error is not really helping.
Is there any way to improve that?

My first import is normalize.css and after taking a look in the <style> element I saw some empty :root elements (due to the fact I use future proof CSS transformed via cssnext).
It seems the parser you are using is kind of outdated for some part.

If you are using csso for minification, would you consider switch to a more fresh tool (csswring) based on an parser with an active development (postcss)?

[jhnns]

PostCSS is backed by Autoprefixer, so it's probably developed more actively. 👍

[MoOx]

postcss 4 is really fast (just run this to check it out https://github.com/postcss/postcss/tree/master/benchmark ) & even support CSS specs that are not implemented in browsers. So seems a really good choice indeed.

[sokra]

Yes, write a PR... I've already tried to use an alternative library in the rework branch.
Check that all test pass and maybe add some for the new stuff.

The rework branch doesn't work out, because it removed the whitespace from css and this would break SourceMap.

[MoOx]

rework is kind of unmaintained (last commit is from august 2014).
More & more people are switching to postcss now that the ecosystem start to be consistent.

[sokra]

yeah... I'm fine if you do a PR with postcss.

[jhnns]

Since a rewrite with PostCSS is probably rather expensive, we should add a quickfix for the status quo because the current problem renders the css-loader useless.

[MoOx]

A rewrite with postcss should be pretty quick since postcss-import can do the inline & postcss-url can do accept a callback to handle what to do with the url.
A "quickfix" should be to fix the parser, which seems heavier to me than using postcss-import + url plugins...

[MoOx]

Oh just saw you fix. Ouch.

[MoOx]

Closing since you now use postcss